CHM 215 Princeton University Final Exam Notes

KHAN ACADEMY BUFFERS PRACTICE PROBLEMS

1 What is the pit of a buffer solution that is 0 24M NHz and 0.20M Nitycl

henderson hasselback right
left
log
H
A
K
P
a
our acid is Nhut from Nhu CI and base is NHz

PH right
left
log
9
0
K
3
5
2
p
7
a
times
H
N
K
6
0
3
5
o
a1r so
times
right
left
log
6
9
K
0
5
2
p
a1
2 If 0.005 mol of Naott is added to d sol of the buffer solution 0 24 M N 13
and 0.20 M Nity Cl what is the resulting pit

MNAOH M
m
0
5
o1l
base so d aim also cott concentration
strong
eve
R
goesto completion
nr
times
strong base
rightarrow
O
H
N
4
3
2
I 0.20 0.01 4
0
2 PH right
frac
left
log
H
A
K
p
a
C 0.01 0.01 0
1
right
left
log
9
0
5
2
1
0.19 9
0
2 9
3
7 still a buffer cue pitbarely
changedE
03
If 0.03 mol of Hcl is added to d sol of the buffer solution co 24 M N H
and 0.20M Nitual what is the pit
3
resulting

rightarrow
MO
N
H
C
6
0
4
R
3
2l
I M
6
0 4
0
2 M
0
2
right
left
8
01
PH log
9
6
0
5
2 c 6
0 6
0 6
0
9
0
E
mdlgwhtsquare


8
0
1 6
0
2
still a buffer we
pit change is not notable

, BUFFER CONCEPTUAL
VIDEOHA
A
buffer resists pH change
by
from soln
removing protons
H HA HA as it reacts w free A
HAadd
acidA
H
A A HAHA
HA A

we have bufferedagainst a
change in pH cue OH ions
O
HA added reacted w Ha removing
HA
HA900
A
base
H
A O
H
A
2 these ions from soln
HA A H
A A


buffer equation H O
H
A
3
2
profline




rightarrow
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O
H
K
3
a
right
H
P
left
log
O
H
A
0
B
K
3
5
a right
left
log
H
A
K
p
o
as right
left
H
A

priaKHAN

ACADEMY
ELECTROCHEMISTRY1
use the standard reduction potentials below to calculate the equilibrium
constant for the reactions at 25 C
following
rightarrow
right
left
A
6
3
2
c
a
sIl cag

varepsilon
right
left
V
4
0
5 cathode red
rightarrow
right
left
A
3
2
q
e
asIl varepsilon
right
left
V
6
0
1 anode ox

right
left
V
4
6
0
5
2
E
o
u
n
e
c
a1t
reaction

rightarrow
right
left
A
6
3
2
e
as1tIl
goesto completion
sono backward
reaction
Kvery
large
rightarrow
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V
6
9
0
K
5
2
E
7 K
0
3
2
1